Citing component maker sources, Digitimes says that Pegatron is building the iPhone 5s in preparation for shipment in September. Unlike other recent iPhone 5 rumors, Digitimes maintains that the iPhone 5 won’t be a major update over the iPhone 4.

Pegatron last year upgraded its equipment, factories and worker numbers to handle iPhone 4 orders, Digitimes points out. The company had the capacity to build 10 million CDMA-compatible iPhone 4s (the Verizon iPhone), but lower than expected sales led to it shipping fewer than 4 million units in the last quarter. Pegatron is also vying against other manufacturers to build iPads and MacBooks for Apple.